The goal of the proposed research is to develop a highly accurate and reproducible method to assess the severity of stenotic lesions in coronary arteriograms as well as in digital subtraction angiographic (DSA) images. The absolute dimensions of coronary stenotic lesions, the percentage stenosis and other geometric parameters will be determined from biplane coronary arteriograms by using an iterative deconvolution technique. We believe that our method will provide an accurate anatomical assessment of atherosclerosis regression or progression in stenotic lesions as well as accurate dimensions of normal blood vessels, with which a reliable blood flow analysis using angiograms can be made for functional evaluation of the stenotic lesion. Specifically, we plan to (1) establish a cinedensitometric system including a drumscanner digitizer and an image analysis computer; (2) determine basic imaging parameters of MTFs, LSFs and characteristic curves in cineangiography; (3) implement a 3D projection technique with a calibration cube to determine the accurate position and orientation of a diseased segment from biplane cinearteriograms; (4) develop an iterative deconvolution technique to determine the profile and size of a blurred vessel by taking into account the LSF of the overall imaging system; (5) develop an automated tracking method of the vascular tree using an algorithm based on a double square box region of search; and (6) quantify the precision and accuracy of our method by using phantom images and clinical arteriograms. In addition, we plan to develop a single-plane approach, as an alternative, to quantify the stenotic lesion in a coronary arteriogram. Although this alternative approach will not be as accurate as our biplane method, the single-plane approach will be useful due to its simplicity and in some cases when biplane images are not available. The usefulness and limitations of this single- plane approach will be studied in comparison with the biplane method and the conventional visual interpretation method. We also plan to develop a stereoscopic approach to the determination of accurate sizes of opacified blood vessels obtained with a DSA system.